1. Field of the Invention
The invention relates to low-foaming gas processing compositions of particular use in gas sweetening processes.
2. Description of the Prior Art
In the gas sweetening process, a gas (e.g., natural gas), is purified of base-reactive impurities, such as carbon dioxide and hydrogen sulfide, typically by treatment with one or more suitably reactive amine compounds. The amine forms an adduct with the base-reactive impurity, thereby removing the impurity from the gas. See, for example, U.S. Pat. Nos. 6,929,680 to Krushnevych et al. and 5,314,672 to Vasil, et al.
There has been much focus on anti-foaming technologies in the areas of detergents, polymer processing, well treating, and waste streams. These antifoaming technologies are generally not well suited for the reduction of foam in gas sweetening processes. See, for example, U.S. Pat. Nos. 3,846,329 to Householder et al., 6,156,808 to Chatterji et al., 6,369,022 to Hoogland et al., 6,512,015 to Elms et al., and 6,521,587 to L'Hostis et al., and C. L. Crawford, “Hydrogen Generation Rate Scoping Study of DOW Corning Antifoam Agent,” ACS 57th Southeast/61st Southwest Regional Meeting, No. 429, Memphis, Tenn.
It is known in the art to include an antifoam composition for the suppression of foam in gas sweetening operations. For example, an antifoaming formulation containing a silicone antifoam component, a polydimethylsiloxane-polyoxyalkylene copolymer emulsifier, and water, in the absence of polypropylene glycol, is commercially available for this purpose under the trade name Sag®7133 (see “OSi Antifoams in the Alkanolamine Process of Gas Scrubbing,” EU-36-018/KS/fk/January, ©2001 Crompton Corporation; and “SAG®7133 and SAG®220,” GE-Advanced Materials, © 2003-2006 General Electric Company).
However, there still remains a need for gas sweetening compositions with more effective foam controlling properties. The present invention is directed to this need.